| A nanocomposite prepared from platinum particles, polyaniline and a Ti3C2 MXene for amperometric sensing of hydrogen peroxide and lactate | |
| Neampet S., Ruecha N., Qin J., Wonsawat W., Chailapakul O., Rodthongkum N. | |
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| A nanocomposite consisting of platinum particles, polyaniline and Ti3C2 MXene (Pt/PANI/MXene) was used to modify a screen-printed carbon electrode (SPCE) to obtain sensors for hydrogen peroxide and lactate. This nanocomposite was characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM) and X-ray powder diffraction (XRD) to determine the physical morphologies and the nanocomposite elements. The modified electrode exhibited the improved current response towards hydrogen peroxide (H2O2) compared with an unmodified electrode and provided a low detection limit of 1.0 μM. When lactate oxidase was immobilized on the modified electrode, the electrode responded to lactate via the H2O2 generated in the enzymatic reaction. The lactate assay was performed by amperometry at a constant potential of +0.3 V (vs. Ag/AgCl). The linear range was found to be from 0.005 to 5.0 mM with a detection limit of 5.0 μM for lactate. Ultimately, this biosensor was used for the determination of lactate in milk samples with high stability and reliability. [Figure not available: see fulltext.]. © 2019, Springer-Verlag GmbH Austria, part of Springer Nature. | |
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| Continuous Flow Selective Hydrogenation of 5-Hydroxymethylfurfural to 2,5-Dimethylfuran Using Highly Active and Stable Cu-Pd/Reduced Graphene Oxide | |
| Mhadmhan S., Franco A., Pineda A., Reubroycharoen P., Luque R. | |
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| 2,5-Dimethylfuran (DMF) has been considered a promising biofuel additive, potentially derived from renewable resources. There have been various reports on DMF production from hydrogenation of 5-hydroxymethylfurfural (HMF). However, most reports employed high hydrogen pressure, long reaction times, and reactions under batch conditions. In this study, Cu-Pd bimetallic catalysts incorporated on reduced graphene oxide (RGO) were used for selective hydrogenation of HMF to DMF using 2-propanol as hydrogen donor under continuous flow conditions. Synthesized catalysts were characterized by N2 physisorption, SEM-EDX, XRD, XPS, TEM, and H2-TPR techniques. 10Cu-1Pd/RGO exhibited 96% HMF conversion with 95% DMF yield under optimum reaction conditions with good stability with time on stream. XRD and XPS results pointed to the presence of a palladium-copper alloy, which could enhance both the activity and especially the stability in the conversion of HMF toward DMF. The effect of temperature, pressure, and feed flow rate were also investigated on the catalytic performance. The stability of catalyst was tested for 8 h time on stream, where it was found that the catalyst displayed good stability. Copyright © 2019 American Chemical Society. | |
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| Binary alloys; Biofuels; Catalysts; Copper alloys; Copper compounds; Graphene; Hydrogen; Hydrogenation; Palladium compounds; Stability; X ray diffraction; X ray photoelectron spectroscopy; 2,5-Dimethylfuran; 5 hydroxymethyl furfurals; Bimetallic catalysts; Continuous flows; Optimum reaction conditions; Palladium-copper alloys; Reduced graphene oxides (RGO); Selective hydrogenation; Palladium alloys | |
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| Hydrodeoxygenation of oleic acid and palmitic acid to hydrocarbon-like biofuel over unsupported Ni-Mo and Co-Mo sulfide catalysts | |
| Yoosuk B., Sanggam P., Wiengket S., Prasassarakich P. | |
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| Second generation biodiesel, so-called bio-hydrogenated diesel (BHD), can be produced from hydrotreatment of vegetable oils. The hydrogenation (HDO) of oleic acid and palmitic acid as model compounds of palm oil over unsupported Ni-Mo and Co-Mo sulfide catalysts was performed in a Parr reactor to produce BHD. The effects of reaction parameters: temperature, hydrogen pressure and the atomic ratio of catalysts (Ni/(Ni + Mo) or Co/(Co + Mo)) on the conversion and product yields (mainly n-C15, n-C16, n-C17 and n-C18 hydrocarbons) were evaluated. The results show that the high pressure favored HDO pathway, while high temperature strongly affected the decarboxylation and decarbonylation pathways. At optimal conditions for oleic acid HDO, the efficient catalyst was NiMoS2 catalyst (Ni/(Ni + Mo) = 0.2) which gave high oleic acid conversion (100%), n-C18 selectivity (78.8%) and n-C18 yield (70.3%) whereas, for palmitic acid HDO, NiMoS2 catalyst (Ni/(Ni + Mo) = 0.2) also gave high palmitic acid conversion (95.2%), n-C16 selectivity (78.5%) and n-C16 yield (65.6%). © 2019 Elsevier Ltd | |
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| Binary alloys; Biofuels; Carboxylation; Catalyst selectivity; Cobalt alloys; Cobalt compounds; Hydrocarbons; Hydrogenation; Molybdenum compounds; Oleic acid; Palm oil; Palmitic acid; Saturated fatty acids; Bio-hydrogenated diesel; Efficient catalysts; Hydrodeoxygenation; Hydrogen pressures; Mo sulfide catalyst; Reaction parameters; Second-generation biodiesels; Sulfide catalysts; Sulfur compounds; biofuel; catalysis; catalyst; chemical compound; decarboxylation; diesel engine; high pressure; high temperature; temperature effect; vegetable oil | |
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| Fe-containing MOFs as seeds for the preparation of highly active Fe/Al-SBA-15 catalysts in the N-alkylation of aniline | |
| Mhadmhan S., Marquez-Medina M.D., Romero A.A., Reubroycharoen P., Luque R. | |
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| We have successfully incorporated iron species into mesoporous aluminosilicates (Al-SBA-15) using a simple mechanochemical milling method. The catalysts were characterized by nitrogen physisorption, inductively coupled plasma mass spectrometry (ICP-MS), pyridine (PY) and 2,6-dimethylpyridine (DMPY) pulse chromatography titration, powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX). The catalysts were tested in the N-alkylation reaction of aniline with benzyl alcohol for imine production. According to the results, the iron sources, acidity of catalyst and reaction conditions were important factors influencing the reaction. The catalyst showed excellent catalytic performance, achieving 97% of aniline conversion and 96% of imine selectivity under optimized conditions. © 2019 by the authors. | |
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| aniline; aniline derivative; iron; metal organic framework; nitrogen; SBA-15; silicon dioxide; adsorption; catalysis; chemistry; ultrastructure; X ray diffraction; Adsorption; Aniline Compounds; Catalysis; Iron; Metal-Organic Frameworks; Nitrogen; Silicon Dioxide; X-Ray Diffraction | |
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| Ca–Mg–Al ternary mixed oxides derived from layered double hydroxide for selective etherification of glycerol to short-chain polyglycerols | |
| Sangkhum P., Yanamphorn J., Wangriya A., Ngamcharussrivichai C. | |
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| In this study, a magnesium (Mg) and aluminum (Al) layered double hydroxide (LDH) was used as a precursor in the preparation of calcium (Ca), Mg and Al ternary mixed oxides for selective conversion of glycerol into diglycerols via solvent-free glycerol etherification. The LDH-derived MgAl mixed oxide was saturated with an aqueous solution of Ca citrate complexes, followed by calcination at 700 °C, to obtain the Ca-MgAl mixed metal oxide (MMO) catalysts. The effects of the citric acid addition and Ca loading levels on the physicochemical and catalytic properties of the resulting Ca-MgAl MMO were investigated. The Ca-MgAl MMO series were characterized by a high Ca dispersion, high total basicity (236–482 μmol g −1 ), an enhanced amount of strong basic sites and a new mesoporosity. The highest diglycerols selectivity of 78.3 mol% was achieved at a glycerol conversion of 40.4 mol% when the reaction was performed over the Ca-MgAl MMO catalyst synthesized with a 7.5 wt% Ca loading level, at a 3 wt% catalyst loading, 220 °C for 24 h. The formation of ternary mixed oxides improved the structural stability of the pristine MgAl mixed oxide. The catalytic performance of Ca-MgAl MMO was compared with that of commercial MgAl mixed oxides and homogeneous base (Na 2 CO 3 ). The presence of strong basicity in the MMO catalysts was a key part in the selective synthesis of diglycerols. © 2019 Elsevier B.V. | |
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| Aluminum alloys; Aluminum oxide; Binary alloys; Catalyst selectivity; Glycerol; Magnesium alloys; Metals; Physicochemical properties; Sodium alloys; Sodium Carbonate; Sodium compounds; Stability; Catalytic performance; Diglycerols; Etherification; Glycerol conversions; Layered double hydroxides; Mixed oxide; Structural stabilities; Ternary mixed oxides; Loading; aluminum oxide; aqueous solution; catalysis; catalyst; citric acid; dehydration; lime; magnesium; physicochemical property | |
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| Post-synthetic Mechanochemical Incorporation of Al-Species into the Framework of Porous Materials: Toward More Sustainable Redox Chemistries | |
| Marquez-Medina M.D., Mhadmhan S., Balu A.M., Romero A.A., Luque R. | |
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| The mechanochemical incorporation of catalytically active Al species in low loadings was successfully accomplished into the framework of mesoporous silica (SBA-15 and MCM-41) materials using a simple wet milling approach (with aluminum isopropoxide as source of aluminum) and a dry milling approach (using low quantities of Al-containing MOF materials). Characterization data pointed to the successful incorporation of Al species (typically with loadings of ca. 0.2-0.4 wt %) that were mostly tetrahedrically coordinated. Despite such extremely low loadings, the isolated aluminum oxide species exhibited promising activities and stability in selective mild oxidations under various conditions (microwave irradiation and mechanochemistry), including the selective oxidation of benzyl alcohol to benzaldehyde, isoeugenol to vanillin, and diphenyl sulfide to diphenyl sulfoxide, as compared to similarly synthesized impregnated catalysts. Copyright © 2019 American Chemical Society. | |
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| Alumina; Aluminum; Crystalline materials; Mesoporous materials; Microwave irradiation; Milling (machining); Oxidation; Silica; Sulfur compounds; Aluminum isopropoxides; Diphenyl sulfoxides; Framework incorporation; Impregnated catalysts; Mechano-chemistry; Mechanochemicals; Mesoporous Silica; Selective oxidation; Aluminum oxide | |
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| Properties of poly(lactic acid) filled with hydrophobic cellulose/SiO 2 composites | |
| Lertphirun K., Srikulkit K. | |
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| Hydrophobic cellulose/SiO 2 composites were prepared. Resultant hydrophobic cellulose/SiO 2 composites were melt mixed with PLA using a twin-screw extruder to obtain 10 wt% masterbatch. Again, 10 wt% masterbatch was melt mixed with virgin PLA, resulting in PLA containing hydrophobic cellulose/SiO 2 at various contents (1 wt%, 3 wt%, and 5 wt%) using a twin-screw extruder (barrel zone temperature: 150/160/170/180/190 ° C (die zone)). Injection-molded samples were prepared for mechanical properties evaluation. Results showed that poor mechanical properties found at low percent loadings were associated with a significant depolymerization of masterbatch composition due to twice thermal treatments. Note that 10 wt% masterbatch was subjected to injection molding straight away in a one-step process. Results showed that 10 wt% hydrophobic cellulose/SiO 2 /PLA composites exhibited mechanical properties equivalent to neat PLA. Importantly, the addition of hydrophobic cellulose/SiO 2 at high percent loading could favor landfill degradation of PLA via water absorption ability of cellulose. It was expected that enzymatic hydrolysis of cellulose resulted in the formation of lactic acid and silicic acid which consequently catalyzed the hydrolytic degradation (acid hydrolysis) of PLA. The hydrolytic degradation produced carboxylic acid end group which further accelerated the degradation rate. Copyright © 2019 Kittithorn Lertphirun and Kawee Srikulkit. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. | |
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| Computational fluid dynamics simulation of system hydrodynamics in a riser of stage circulating fluidized bed reactor | |
| Phupanit J., Soanuch C., Korkerd K., Piumsomboon P., Chalermsinsuwan B. | |
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| The riser of conventional and stage circulating fluidized bed reactors were simulated using computational fluid dynamics. The objective was to examine the design parameter effects using a 23 statistical experimental design method. The results showed that number of reactor stages had the highest effect on the standard deviation of the solid volume fraction (SVF), the average SVF, and standard deviation of gas temperature in a horizontal direction. In addition, the reactor wall temperature had the highest effect on the average holding time of catalysts. Increasing the number of reactor stages could reduce the back-mixing and increase the system turbulence. The average vertical and horizontal solid particle velocities in the reactor stage region were higher than in the other regions. At the reactor stage region, peaks in the gas temperature were observed. The advantages of a stage reactor were confirmed to be applied in all the operating condition cases, independent of the solid particle mass flux. © 2018 Curtin University and John Wiley & Sons, Ltd. | |
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| Chemical reactors; Computational fluid dynamics; Fluidized bed furnaces; Fluidized bed process; Hydrodynamics; Mixing; Non Newtonian flow; Statistics; Supersaturation; Circulating fluidized bed reactor; Computational fluid dynamics simulations; Design parameters; Operating condition; Solid particles; Solid volume fraction; Standard deviation; Statistical experimental design; Fluidized beds | |
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| Filter paper grafted with epoxide-based copolymer brushes for activation-free peptide nucleic acid conjugation and its application for colorimetric DNA detection | |
| Leekrajang M., Sae-ung P., Vilaivan T., Hoven V.P. | |
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| Epoxide-bearing filter paper was first prepared by surface-initiated reversible addition-fragmentation chain transfer (RAFT) copolymerization of glycidyl methacrylate (GMA) and poly(ethylene glycol)methacrylate (PEGMA). Without the need for activation step, the capture peptide nucleic acid (PNA) probes carrying a C-terminal lysine modification can be directly immobilized on the surface-grafted poly[glycidyl methacrylate-ran-poly(ethylene glycol)methacrylate] (P(GMA-ran-PEGMA)) through ring-opening of epoxide groups in the GMA repeating units by amino groups in the PNA’s structure. The success of P(GMA-ran-PEGMA) grafting on the filter paper and subsequent PNA immobilization was confirmed by fluorescence microscopy, Fourier transform-infrared spectroscopy and X-ray photoelectron spectroscopy. Colorimetric detection with signal amplification upon DNA hybridization relies on sandwich-hybridization assay employing another biotinylated PNA strand as a reporter probe together with streptavidin-horseradish peroxidase conjugate (SA-HRP) and o-phenylenediamine (OPD) substrate. It was found that increasing ionic strength during the DNA hybridization step by addition of NaCl can increase the signal intensity, which can be visualized by naked eye. The sensing platform showed the best performance in preventing non-specific adsorption from the non-complementary DNA and discriminating between complementary and single-mismatched targets of at least 50 fmol without the requirement for stringent hybridization or washing condition. This superior ability to suppress non-specific adsorption of non-target DNA as well as other non-DNA components may be explained as a result of hydrophilic PEGMA repeating units in the surface-grafted copolymer. © 2018 Elsevier B.V. | |
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| Acrylic monomers; Adsorption; Amino acids; Biomolecules; Chemical activation; Color; Colorimetry; Copolymerization; DNA; Ethylene glycol; Fluorescence microscopy; Fourier transform infrared spectroscopy; Free radical polymerization; Grafting (chemical); Ionic strength; Paper; Peptides; Polyethylene glycols; Polyols; Probes; Sodium chloride; X ray photoelectron spectroscopy; Colorimetric detection; DNA sensors; Enzymatic amplifications; Epoxide groups; Filter papers; Nonspecific adsorption; Peptide nucleic acid; Polymer brushes; Sandwich hybridization; Nucleic acids; carbon; complementary DNA; copolymer; epoxide; fluorine; glycidyl methacrylate; horseradish peroxidase; oxygen; peptide nucleic acid; phenylenediamine; poly(ethylene glycol)methacrylate; sodium chloride; streptavidin; unclassified drug; 1,2-diaminobenzene; 2 hydroxyethyl methacrylate; DNA; epoxide; glycidyl methacrylate; HLA antigen; macrogol; methacrylic acid; peptide nucleic acid; phenylenediamine derivative; polyethylene glycol methacrylate; polymer; adsorption; Article; biotinylation; catalyst; colorimetry; conjugation; controlled study; DNA determination; DNA hybridization; DNA sequence; enzyme immobilization; filter paper; fluorescence microscopy; Fourier transform infrared spectroscopy; ionic strength; limit of detection; molecular weight; polymerization; priority journal; proton nuclear magnetic resonance; ring opening; surface property; X ray photoemission spectroscopy; allele; chemistry; colorimetry; filtration; human; infrared spectroscopy; nuclear magnetic resonance spectroscopy; nucleic acid hybridization; procedures; software; Adsorption; Alleles; Colorimetry; DNA; Epoxy Compounds; Filtration; HLA Antigens; Horseradish Peroxidase; Humans; Magnetic Resonance Spectroscopy; Methacrylates; Nucleic Acid Hybridization; Peptide Nucleic Acids; Phenylenediamines; Polyethylene Glycols; Polymerization; Polymers; Software; Spectroscopy, Fourier Transform Infrared; Surface Properties | |
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